The 'mourning' of white-naped jays (Corvidae)

At 18:15 today, Brasília time, I observed a flock of white-naped jays (Cyanocorax cyanopogon) vocalising stridently as a group. I identified that type of vocalisation as a distress signal of some kind. I thought maybe they had spotted a snake.

I observed at a distance of about 10m to see the source of their distress. They were circling a small area, perched atop surrounding tree branches, and looking at the ground as a group. The vocalization of this small group was of a single type, while the individuals acting as sentinels further from this circle were vocalizing differently, but also repeatedly.

I decided to inspect the area they were vocalizing towards. They fled as I approached and stopped vocalizing. They flew away. I looked for any predator, such as a snake, and found nothing. But I did find a dead individual of the same species. I poked it and turned it. It showed rigor mortis, and some sarcophagids were already there. The disposition of the feathers suggests the animal died in a violent fashion.

So, in conclusion, it seems the white-naped jays were not in distress for having seen a predator. This area is in the vicinity of our farm house, and all our cats were inside at the time. Dogs were far from the area. The most likely hypothesis seems to be that a cat killed the animal hours earlier, and the jays had only now discovered its corpse. Agitated by the sight of the body, or maybe the decaying smell (not strong yet for a human), they started to vocalise frantically, as if in 'mourning'. Corvids are very intelligent, so it doesn't seem far fetched to say so.

There are 9 species of corvids in Brazil, all of them belonging to the genus Cyanocorax.

Posted on February 19, 2019 10:06 PM by